quoting in descriptors

Signed-off-by: Owen Williams <[email protected]>

Author: ywwg

docs/specs/om/open_metrics_spec_1_1.md

@@ -316,9 +316,9 @@ metricset = *metricfamily
 
 metricfamily = *metric-descriptor *metric
 
-metric-descriptor = HASH SP type SP metricname SP metric-type LF
-metric-descriptor =/ HASH SP help SP metricname SP escaped-string LF
-metric-descriptor =/ HASH SP unit SP metricname SP *metricname-char LF
+metric-descriptor = HASH SP type SP (metricname / metricname-utf8) SP metric-type LF
+metric-descriptor =/ HASH SP help SP (metricname / metricname-utf8) SP escaped-string LF
+metric-descriptor =/ HASH SP unit SP (metricname / metricname-utf8) SP *metricname-char LF
 
 metric = *sample
 
@@ -436,6 +436,8 @@ A double backslash SHOULD be used to represent a backslash character.
 A single backslash SHOULD NOT be used for undefined escape sequences.
 As an example, `\\\\a` is equivalent and preferable to `\\a`.
 
+Escaping MUST also be applied to quoted UTF-8 strings.
+
 ##### Numbers
 
 Integer numbers MUST NOT have a decimal point. Examples are `23`, `0042`, and `1341298465647914`.